This invention concerns the control of a motor vehicle wiper.
It is common knowledge to command the wiper system from the dashboard by means of a system allowing one to choose different modes of operation: stop, high speed, low speed, and intermittent. The choice of these modes depends on the quantity of water on the windshield of the vehicle, which is itself a function of a number of elements, the main ones being the intensity of the rain and the flux of air generated by the movement of the vehicle. The change of these conditions, notably the first, is sometimes very progressive and imperceptible such that the driver, whose attention is first and foremost focused on the driving of the vehicle does not always think of the opportune moment to change the mode of operation of the wiper system for the new conditions. One hopes to put in place a system helping wholly or partially the driver in controlling the wiping device, most of the systems proposed until the present have not given full satisfaction.
A goal of this invention is to furnish a system performing control of the wiper.
In order to achieve this goal, this invention conceives of a method for controlling a motor vehicle wiper motor comprising steps which consist of determining at least a range related to an operating parameter of the motor and capable of having several non null values, comparing the range with a predetermined threshold, and controlling the motor on the basis of the result of the comparison, in which the range is determined when the rotor of the motor occupies a determining position corresponding to a predetermined point on a trajectory of a blade driven by the motor.
Thus, the determination of the range while the blade is in a predetermined position of its trajectory makes this determination particularly pertinent and, in addition, reproducible. The control of the motor that as a result is thus also pertinent, reproducible and reliable. By comparison, the measure of the range on the entire trajectory of the blade and the calculation of the corresponding average would be of little pertinence, or even misleading. For example, in the course of the trajectory of the blade, the wind sometimes pushes the blade, sometimes to help it. The calculation of an average can thus make the influence of the wind undetectable. The control decision that would follow would thus not be pertinent.
Advantageously, the motor would be linked to the blade via a connecting rod, the point being in a quasi-linear zone on the basis of transfer from the connecting rod. Thus, the determination of the range is particularly pertinent.
The parameter can comprise the intensity of an electric current supply from the motor.
In effect, this range is directly correlated to the speed of the motor. Also knowing this range, one can compare it to a consigned value or a threshold and control, as necessary, a modification of the operation of the motor such as a modification of motor speed.
The parameter can also include a speed of the motor and/or a position of the rotor of the motor.
Advantageously, the range is an average of several values of the parameters.
One thus avoids giving too much importance to an untimely abrupt variation in the form of a peak.
Advantageously, one will make comparisons of the range with a predetermined lower and upper threshold and the motor is controlled on the basis of these comparisons. Thus, one can control a change in the mode of the motor operation.
Advantageously, the motor will be constructed in order to operate following at least two methods of operation associated to the intervals of different speeds and/or to the different procedures, at least one of the lower and upper thresholds being predetermined on the basis of the current mode of operation of the motor.
Advantageously, one determines the range while a rotor of the motor has a rotational direction corresponding to movement in a predetermined direction on a trajectory of a blade driven by the motor.
Advantageously, the movement direction is such that the blade moves towards the bottom of a windshield of the vehicle.
Thus, in this sense, the blade moves in a direction opposite to the flux of air generated by the displacement of the vehicle moving forward. This performance of the blade is thus more representative of the conditions of the windshield than in the other direction.
Advantageously, one controls the motor on the basis of data given by a wiper control instrument accessible to the driver of the vehicle.
Following the chosen configuration for the system, one will choose the order of priority attached to each mode to an order coming from such a control instrument.
Advantageously, one controls the motor on the basis of a data given by a rain sensor. However, preferably, the rain sensor will only operate in conjunction with the starting of the motor.
Advantageously, one controls the motor on the basis of representative data of the speed of the vehicle.
Advantageously, one controls two vehicle wiper motors, and the system comprising steps which consist of determining two positions of rotors respective to the motors, in order to create a comparison of the positions between them and/or the comparisons of the positions with the thresholds of predetermined respective position, and to control at least one of the motors on the basis of a result of the comparison and/or the results of the comparisons.
Without requiring a mechanical link between the blades, one assures a control of the synchronization of their movements, which is important when the blades are associated to the same windshield and have secant trajectories.
Advantageously, when the parameter is the electric voltage to the motor terminals, one creates a comparison of the range with a predetermined saturation threshold, and one controls a stop of the motor on the basis of a result of the comparison.
One has thus conceived of a wiper motor interruption resulting from a blockage of the blade.
Advantageously, one controls the restarting of the motor after a predetermined interval of time.
Advantageously, the control step includes the modification of a motor speed.
Advantageously, the motor is constructed in order to function following at least two methods of operation associated to the different speed range and/or to the different processes, the control step including the ability to modify a motor speed, and eventually, to change the current mode of operation of the motor.
Advantageously, one controls the motor while a rotor of the motor occupies a control position corresponding to a predetermined point on a trajectory of a blade driven by the motor.
Advantageously, the point is an end of the trajectory of the blade.
Advantageously, one controls the motor in such a way that, for a course of a blade driven by the motor in only one direction from a first end to a second end of the course, the motor has first a constant speed on a first, larger part of the course, then a second constant speed, lower than the first speed on a second part of the course following the first part and preceding the second end.
The invention also conceives a control device of a motor vehicle wiper motor including means for determining at least a range linked to a operating parameter of the motor and capable of having several non null values, means for comparing the range with a predetermined threshold, means for controlling the motor on the basis of the result of the comparison, in which the determination means are constructed in order to determine the range while a rotor of the motor occupies at least one position corresponding to a predetermined point on a trajectory of a blade driven by the motor.
The invention also conceives a reduction motor for a motor vehicle wiper, including a control device according to the invention.